1. Technical Field
The present invention relates to preparation of a specimen suitable for observation under a transmission electron microscope (TEM), which reflects the true distribution status of nanoparticles in a blood sample, either in dispersion or agglomeration.
2. Description of Related Art
FIG. 1A-E show a first specimen prepared according to a traditional method.
FIG. 1A shows a traditional substrate 10, which is usually a piece of copper.
FIG. 1B shows a drop of blood sample 11 placed on the top surface of the substrate 10. The blood sample 11 contains, among others, nanoparticles 11N, and blood cells 11C. The average diameter of a red blood cell (RBC) is 6 to 8 micrometers. The average diameter of a white blood cell (WBC) is 10 to 12 micrometers. A blood cell 11C has a dimension in μm, which is larger than the dimension of a nanoparticle.
FIG. 1C shows a drop of blood sample 11 evaporates during drying. The drop of blood sample shrinks and a plurality of smaller droplets are formed. The surface tension 13 of each droplet drags the components therein closer and closer. The components undergo gatherings.
FIG. 1D illustrates two groups of aggregates A1 of nanoparticles 11N are formed. The concentrating effect of the components within each droplet is caused by a surface tension 13 during drying, causing formation of aggregates A1 of nanoparticles. The aggregates A1 of nanoparticles in the prepared sample had appearances similar to nanoparticle-agglomerates, which may cause a confusion between aggregates and agglomerates and give wrong information to an observer when observing under TEM.
FIG. 1E shows a top view of FIG. 1D. Two groups of aggregates A1 of nanoparticles 11N are formed. The specimen of FIG. 1E does not reflect the true status of nanoparticles 11N, which is evenly dispersed in the blood sample 11 as evidenced by FIG. 1B.
Now, paying attention to nanoparticles 11N only. One of the purposes to examine a specimen of blood sample is to observe the status of nanoparticles 11N in the original blood sample, either in dispersion or agglomeration. However, a specimen prepared by a traditional method does not reflect the original or true status of nanoparticles 11N in the original blood sample, either in dispersion or agglomeration. As shown in FIGS. 1D-E, which shows aggregates A1 of nanoparticles 11N, false information has been displayed under TEM due to a surface tension 13 between the droplets during drying. It is desired that the true status of nanoparticles 11N in the original blood sample can be reflected, either in dispersion or agglomeration.
FIGS. 2A-E show a second specimen prepared according to a traditional method.
FIG. 2A shows a traditional substrate 10, a copper grid.
FIG. 2B shows a drop of blood sample 11 placed on the top surface of the substrate 10. The blood sample 11 contains, among others, dispersed nanoparticles 11N, nanoparticle-agglomerates 11NA, and blood cells 11C.
FIG. 2C shows the liquid evaporates during drying, the drop of blood sample shrinks and smaller droplets are formed. The surface tension 13 of each droplet drags the components closer and closer.
FIG. 2D shows aggregates A2 of nanoparticles are formed.
FIG. 2E shows the top view of FIG. 2D. Two groups of aggregates A2 of nanoparticles 11N are formed. Actually, the aggregates A2 do not exist in the original blood sample, see FIG. 2B. The specimen of FIG. 2E gives false information to an observer.
Now, paying attention to nanoparticle-agglomerates 11NA only. One of the purposes to examine a specimen of a blood sample under TEM is to observe whether any nanoparticle-agglomerate exists in an original blood sample. However, a specimen prepared by a traditional method does not reflect the true number of nanoparticle-agglomerates 11NA. Several aggregates A2 of nanoparticles 11N, counterfeits of nanoparticle-agglomerates 11NA, are present in FIGS. 2D-E. The aggregates A2 are caused by the surface tension 13 of the droplets during drying. It is desired that the true situation of nanoparticles in the specimen can be observed, either in dispersion or agglomeration.